Polymers, in particular block copolymers, which self-assemble into nanostructures have been proposed for use in a number of applications including filtration membranes, pervaporation membranes, lithography, solid state polymer electrolytes, ion exchange membranes, and biomaterials. For example, diblock copolymers when dissolved in selective solvents self-assemble into spherical or cylindrical micelles, vesicles and other structures. However, challenges remain in obtaining well defined nanostructures. The foregoing indicates that there is an unmet need for block copolymers that self-assemble under appropriate processing conditions to provide well defined nanostructures.